Design Requirements · Requirement 8 of 27

Site studies — sun path and wind direction

Autodesk Forma sun and wind studies, plus a quarterly climate analysis from the Yanbu station normals and 34 years of ERA5 data – Q1 outdoor season, Q3 peak heat (40.5 °C mean max), W–NW sea breeze, warming trend to 2030.

✓ CompliedRC presentation REV09 · p. 17–23

Answer

Autodesk Forma (original): 9+ sun hours on the site and roofs on 21 June; sunset azimuth moves 51 deg (293 deg June - 242 deg December), always over the sea.

Wind: NEN 8100 / Lawson at 1.75 m, 17 runs - 0 % uncomfortable at grade; podium and pool deck sitting-grade; roof terraces (+32.00 roof level) exposed to W-NW breeze - answered with a 40-50 % porous screen 1.8-2.1 m high.

Quarterly climate analysis (supplement, 8 Nov 2026 – https://rcjy.d57.space/climate/): Yanbu station normals 1991–2020 (WMO 40439) and ERA5 reanalysis 1991–2024 at the site. Q1 Jan–Mar: mean max 29.3 °C, 80 % comfortable hours – the outdoor season. Q2 Apr–Jun: 38.0 °C, strongest afternoon W–WNW sea breeze (7–8 m/s). Q3 Jul–Sep: 40.5 °C (record 51.0 °C), nights about 27–28 °C, 1 % comfortable hours, 38 % of the yearly cooling degree days – the design cooling season. Q4 Oct–Dec: 33.3 °C, 29 of the 39 mm annual rain. Wind from the WSW–NW for 43–64 % of hours. Observed warming 0.34–0.62 °C per decade; trend projection for 2030: Q3 mean max about 42 °C. Data agree with the Forma sun, wind and solar studies.

Key data and sources

Each figure with the drawing, study or standard it comes from.

Item	Value	Source
Sun hours 21 June	>= 9 h site and roofs	Autodesk Forma
Sunset azimuth	242 deg (Dec) - 293 deg (Jun), 51 deg sweep	Autodesk Forma
Wind at 1.75 m (17 runs)	0 % uncomfortable	Autodesk Forma, NEN 8100 / Lawson
Roof screen	40-50 % porous, 1.8-2.1 m high, W-NW arc	Autodesk Forma